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Published on: October 16, 2010
Birth weight as a risk factor for breast cancer: a meta-analysis of 18 epidemiological studies
Xiaohui Xu1, Amy B Dailey, Mary Peoples-Sheps
1Department of Epidemiology & Biostatistics, College of Public Health and Health Professions, University of Florida, Gainesville, FL 32610-0231, USA. xhxu@phhp.ufl.edu
Background:
Birth weight has been identified as a birth-related factor associated with the risk of breast cancer. However, the evidence is inconsistent.
Methods:
To investigate the association between birth weight and breast cancer, we conducted a meta-analysis of published studies between 1996 and 2008. Eighteen studies encompassing 16,424 breast cancer cases were included in the meta-analysis. Data were combined using a fixed-effect or random-effect model depending on the heterogeneity across studies.
Results:
Women with their own birth weight >4000 g or 8.5 lb had a higher risk for developing breast cancer than those with birth weight <2500 g or 3000 g (OR = 1.20, 95% CI 1.08, 1.34). Findings were also consistent with a dose-response pattern effect. The summary effect estimate for breast cancer risk per 1 kg increase in birth weight was statistically significant (random effects OR = 1.07, 95% CI 1.02, 1.12).
Conclusions:
Although these results provided no evidence indicating whether birth weight is more strongly related to early-onset than to later-onset breast cancer, our findings suggest an association between birth weight and breast cancer. The underlying biological mechanism relating to this phenomenon needs additional study.
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